HIN232 Intersil Corporation, HIN232 Datasheet - Page 8

• Manufacturer Part Number: HIN232
• Description: +5V Powered RS-232 Transmitters/Receivers
• Manufacturer: Intersil Corporation

Detailed Description
The HIN232 thru HIN241 family of RS-232
transmitters/receivers are powered by a single +5V power
supply (except HIN239), feature low power consumption, and
meet all ElA RS-232C and V.28 specifications. The circuit is
divided into three sections: The charge pump, transmitter, and
receiver.
Charge Pump
An equivalent circuit of the charge pump is illustrated in Figure
1. The charge pump contains two sections: the voltage
doubler and the voltage inverter. Each section is driven by a
two phase, internally generated clock to generate +10V and
-10V. The nominal clock frequency is 16kHz. During phase
one of the clock, capacitor C1 is charged to V
phase two, the voltage on C1 is added to V
signal across C3 equal to twice V
also charged to 2V
inverted with respect to ground to produce a signal across C4
equal to -2V
to 5.5V. The output impedance of the voltage doubler section
(V+) is approximately 200Ω, and the output impedance of the
voltage inverter section (V-) is approximately 450Ω. A typical
Electrical Specifications
NOTE:
Output Enable Time, t
Output Disable Time, t
Propagation Delay, t
Instantaneous Slew Rate SR
Transition Region Slew Rate, SR
TRANSMITTER OUTPUTS
Output Voltage Swing, T
Output Resistance, R
RS-232 Output Short Circuit Current, I
4. Guaranteed by design.
OSCILLATOR
GND
V
CC
RC
CC
. The charge pump accepts input voltages up
PARAMETER
CC
PD
OUT
EN
DIS
S1
S3
, and then during phase two, it is
OUT
VOLTAGE DOUBLER
8
T
C1
Test Conditions: V
C1-
CC
+
+
-
SC
. During phase one, C2 is
C1
S2
S4
CC
CC
, producing a
HIN236, 239, 240, 241
HIN236, 239, 240, 241
RS-232 to TTL
C
R
-3V to +3V, 1 Transmitter Switching
Transmitter Outputs, 3kΩ to Ground
V
T
OUT
CC
L
L
. During
CC
= 3kΩ, C
= 10pF, R
= V+ = V- = 0V, V
= +5V ±10%, T
shorted to GND
+
FIGURE 1. CHARGE PUMP
-
C3
V
L
CC
L
= 2500pF Measured from +3V to -3V or
= 3kΩ, T
TEST CONDITIONS
V+ = 2V
A
OUT
= Operating Temperature Range (Continued)
A
GND
= 25
application uses 1µF capacitors for C1-C4, however, the value
is not critical. Increasing the values of C1 and C2 will lower the
output impedance of the voltage doubler and inverter,
increasing the values of the reservoir capacitors, C3 and C4,
lowers the ripple on the V+ and V- supplies.
During shutdown mode (HIN236, 240 and 241),
SHUTDOWN control line set to logic “1”, the charge pump is
turned off, V+ is pulled down to V
and the supply current is reduced to less than 10µA. The
transmitter outputs are disabled and the receiver outputs are
placed in the high impedance state.
Transmitters
The transmitters are TTL/CMOS compatible inverters which
translate the inputs to RS-232 outputs. The input logic threshold
is about 26% of V
input results in a voltage of between -5V and V- at the output,
and a logic 0 results in a voltage between +5V and (V+ -0.6V).
Each transmitter input has an internal 400kΩ pullup resistor so
any unused input can be left unconnected and its output
remains in its low state. The output voltage swing meets the
RS-232C specifications of ±5V minimum with the worst case
conditions of: all transmitters driving 3kΩ minimum load
CC
= ±2V
o
C (Note 4)
S5
S7
VOLTAGE INVERTER
C2
C2
CC
+
+
-
-
C2
, or 1.3V for V
S6
S8
MIN
300
±5
-
-
-
-
-
-
CC
CC
TYP
, V- is pulled up to GND,
400
250
±10
0.5
+
±9
-
= 5V. A logic 1 at the
3
-
-
C4
MAX
±10
30
-
-
-
-
-
-
GND
V- = -(V+)
UNITS
V/µs
V/µs
mA
ns
ns
µs
Ω
V